Allen predicted he would win if Fu decided it was a "grudge match", following comments made by the man from Antrim during the World Championship in April when he claimed his opponent had cheated in the past.

There appeared little animosity between the pair as they shook hands following Fu's 6-3 victory at York's Barbican Centre.

But on a day when it emerged the World Professional Billiards and Snooker Association (WPBSA) had written to Allen to ask him to explain his comments of last Wednesday, when he reiterated that he believed Fu had cheated in the past, it was a tough loss for the world number eight.

In Sunday night's other match, Stuart Bingham scored a resounding 6-2 win this evening against 21-year-old Jack Lisowski to set up a second-round match against Stephen Maguire.

Earlier, world number one Judd Trump saw his hopes of successfully defending the title shattered by a first-round exit at the hands of Mark Joyce.

Trump led 5-2 and was seemingly heading for a comfortable win in the best-of-11 contest, but Walsall journeyman Joyce produced a startling fightback to win 6-5.

Trump's concentration looked to slip and form certainly deserted him, with Joyce taking advantage to set up a second-round clash against World Championship runner-up Ali Carter, a 6-2 winner over 55-year-old Steve Davis.

"Nothing seemed to go right. I didn't play well," said Trump. "It's disappointing.

"I'd done well to go 5-2 in front but I didn't really have any clear-cut chances after that and my long-potting was just awful. You can't win them all."

Carter launched his challenge with a scrappy win over Davis.

Both men struggled for fluency, Carter's highest break of 88 and an 85 from Davis in the seventh frame quite out of keeping with the flow of the match.

Yet Carter was the most consistent of the two, with the 33-year-old from Tiptree in the end a convincing winner over the 55-year-old Brentwood veteran.

Davis struggled with his long-potting and said: "Ali's a very strong player. I didn't really perform well enough. It was a relatively easy day out for Ali.

"I'm disappointed but I shouldn't get too upset because I did qualify. It's nice to play better out there than that.

"Ali's a potential winner of the tournament so I shouldn't moan.

"I expect him to win something big in the next couple of years."

Earlier China's dismal tournament continued as Cao Yupeng became the third player from snooker's boom nation to make a first-round exit.

Youngster Cao, who caused a stir in April by beating Mark Allen in the first round of the World Championship, never looked likely to build on that as he tumbled out 6-1 against veteran Hastings potter Mark Davis.

Cao joins a casualty list of Chinese players that began with defeats for Liang Wenbo and former UK champion Ding Junhui.

Shaun Murphy was UK champion in 2008 and the Manchester-based 30-year-old began another campaign with a comfortable enough 6-3 win over Gloucester's Robert Milkins.